Multifunctional porous NiCo bimetallic foams toward water splitting and methanol oxidation-assisted hydrogen production

Abstract

Multifunctional electrocatalysts with high catalytic activity and selectivity are highly desirable for environmentally benign and sustainable energy conversion and storage technologies such as fuel cells, electrocatalytic water splitting, rechargeable batteries, etc. Herein, we report the fabrication of 3D nanostructured porous NiCo bimetallic foams on Cu foil electrodes by a simple, ultrafast, and single-step dynamic bubbles templating electrodeposition method. Porous NiCo foam showed remarkable electrocatalytic activity for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and methanol oxidation-assisted hydrogen production in an alkaline electrolyte. NiCo foam displayed just 85 mV of overpotential for HER to get a current density of 50 mA cm−2, 290 mV of overpotential for OER to attain 20 mA cm−2 of current density in 1 M KOH. In addition, NiCo foam exhibited good selectivity for methanol oxidation to yield valuable formate product by applying a potential of 1.33 V for 20 mA cm−2 with the co-generation of hydrogen gas in alkaline methanol–water solution due to excellent electronic conductivity, high internal reactive surface areas, profiting electrolyte accessibility, and effective mass transfer at the electrolyte/electrode interface of this foam. Furthermore, this electrocatalyst demonstrated bifunctional activities, requiring just 1.67 V and 1.47 V to attain 20 mA cm−2 of current density for overall bifunctional water splitting and methanol-assisted water splitting, respectively. This work emphasizes the favorable impact of self-supported interconnected metallic porous networks with bimetallic synergistic effect and high surface area on the advancement of more effective electrocatalysts for water splitting and energy saving hydrogen production.